1. Field of the Invention
The present invention relates to an edge exposure apparatus for performing exposure for an edge portion of a substrate coated with a photosensitive material such as a resist or the like by applying light thereto, a coating and developing apparatus using the edge exposure apparatus, and an edge exposure method.
2. Description of the Related Art
As an apparatus for forming a resist pattern on a substrate such as a semiconductor wafer (hereinafter, referred to as a wafer), for example, a coating and developing apparatus is employed which applies a photoresist (hereinafter, referred to as a resist) for the wafer and develops the wafer which has been exposed to light in an aligner. In this coating and developing apparatus, the application of the resist is performed in particular by supplying the resist onto the wafer being rotated so that the resist spreads over the front surface of the wafer by a centrifugal force, so that the resist is applied over the entire front surface of the wafer. A peripheral portion (an edge portion) of the wafer, however, is rarely used as a pattern formation region, and therefore the peripheral portion may not be exposed in the aligner. In that case, a positive-type resist, when used as the aforementioned resist, remains on the peripheral portion even after development. This resist can peel off, for example, during carriage of the wafer into particles which contaminate the front surface of the wafer, causing a decrease in yield.
To prevent such a trouble, an edge exposure apparatus for exposing the peripheral portion of the wafer is provided in the coating and developing apparatus. The edge exposure apparatus is provided, for example, in an interface section which serves to connect the coating and developing apparatus and an aligner for performing exposure processing to form a resist pattern. Edge exposure processing is performed by the edge exposure apparatus for the wafer before subjected to exposure in the aligner, and developing treatment is then performed so that an unnecessary resist at the peripheral portion of the wafer is removed.
However, the throughput of wafers required in the coating and developing apparatus increases in recent years, and it is required to attain a throughput of, for example, 180 to 200 wafers per hour in these days. To increase the throughput, it is conceivable, for example, to additionally provide edge exposure apparatuses in the aforementioned interface section. The provision of additional apparatuses, however, can increase the size of the interface section or fail to ensure a sufficient space to perform maintenance of the edge exposure apparatuses and change of lamps (light sources) in the interface section. The provision of additional edge exposure apparatuses increases the total of the amounts of heat ration from the light sources provided in the edge exposure apparatuses, thus presenting a concern about increasing the effect exerted on other modules in the interface section.
The Japanese Patent Application Laid-open No. Hei 11-219894 discloses a down-sized edge exposure apparatus targeted to simplify a mechanism of aligning a wafer, and discloses no teaching about the means for solving the problem relating to the above-described throughput. The Japanese Patent Application Laid-open No. 2003-347187 discloses an edge exposure apparatus targeted to increase the throughput which has, however, an apparatus configuration assuming that a plurality of light sources are provided, and discloses no teaching about the means for solving the above-described problem.